High efficiency low pollution hybrid Brayton cycle combustor

ABSTRACT

A power generating system is described which operates at high pressure and utilizes a working fluid consisting of a mixture of compressed non-flammable air components, fuel combustion products and steam. The working fluid exiting the power generating system is substantially free of NOx and CO. 
     Working fluid is provided at constant pressure and temperature. Combustion air is supplied by one or more stages of compression. Fuel is injected at pressure as needed. At least about 40% of the oxygen in the compressed air is consumed when the fuel is burned. Inert liquid is injected at high pressure to produce working an inert mass of high specific heat diluent vapor for use for internal cooling of the combustion chamber. 
     The use of non-flammable liquid injection inhibits the formation of pollutants, increases the efficiency and available horsepower from the system, and reduces specific fuel consumption. Control systems allow the independent control of the quantity, temperature and pressure of the air, fuel and non-flammable liquid introduced in the combustion chamber allowing control of the maximum temperature and average temperature within the combustion temperature as well as the temperature of the exhaust from the combustion chamber.

This application is a continuation-in-part of U.S. application Ser. No.08/232,047 filed Apr. 26, 1994 now U.S. Pat. No. 5,743,080 which is theU.S. National Stage of PCT/US93/10280 filed Oct. 27, 1993 and acontinuation-in-patent of Ser. No. 07/967,289, U.S. Pat. No. 5,617,719filed Oct. 27, 1992 all of which are incorporated by reference.

FIELD OF THE INVENTION

The present invention is directed to a vapor-air steam engine whichoperates at high pressure and utilizes a working fluid consisting of amixture of fuel combustion products and steam with a minimal amount ofexcess compressed air. The invention is further directed to processesfor producing electrical energy, usable shaft horsepower and/or largequantities of steam in a fuel burning system at high efficiency and lowspecific fuel consumption, while generating insignificant amounts ofenvironmental pollutants (NO_(x), CO, particulates, unburned fuel). Theinvention is still further directed to the production of potable waterwhile generating electrical power without polluting the environment orsignificantly reducing the efficiency or increasing the fuelconsumption.

BACKGROUND OF THE INVENTION

Internal combustion engines are generally classified as either constantvolume or constant pressure. Otto cycle engines operate by explodingvolatile fuel in a constant volume of compressed air while diesel cycleengines burn fuel in a modified cycle, the burning being approximatelycharacterized as constant pressure.

External combustion engines are exemplified by steam engines, steamturbines and gas turbines. It is well known to supply a gas turbine witha gaseous working fluid generated by combusting a fuel with compressedair and to operate various motor devices from energy stored in this highpressure gaseous stream. In these devices, temperature control isusually the result of feeding large quantities of excess compressed air.

It is also known to burn fuel in a chamber and exhaust the combustionproducts into a working cylinder or chamber, sometimes with theinjection of small quantities of water or steam. These may also beclassified as external combustion engines.

Some other devices have been proposed in which combustion chambers arecooled by addition of water or steam provided either internally orexternally. Still another form of apparatus has been proposed foroperation on fuel injected into a combustion cylinder as the temperaturefalls, having means to terminate fuel injection when the pressurereaches a desired value.

Each of these prior engines has encountered difficulties which limittheir general adoption as a power source for the operation of primemovers. Among these difficulties have been the inability of such anengine to meet sudden demand and/or to maintain a constant workingtemperature or pressure as may be required for efficient operation ofsuch an engine.

Furthermore, control of such engines has been inefficient, and theability of the gas generator to maintain itself in standby condition hasbeen wholly inadequate. In all practical applied engine configurationsthe requirement for cooling the confining walls of the work cylindershas resulted in loss of efficiency and a number of other disadvantagespreviously inherent in internal combustion engines.

The present invention overcomes the limitations of the prior artdescribed above. First, the requirement of large amounts of excesscompressed air or external liquid cooling is eliminated by injectingwater directly into the combustion chamber to control the temperature ofthe resulting working fluid. When water is injected it is convertedinstantaneously into steam in the combustion chamber, and it becomes acomponent of the working fluid itself, thus increasing the mass andvolume of the working fluid without mechanical compression.

In the present invention, independent control of the a) combustion flametemperature b) combustion chamber temperature profile by liquid waterinjection and c) fuel to air ratio allows the physical properties of theworking fluid to be optimized for high efficiency operation. Reducing oreliminating excess air, thus limiting the availability of excess oxygen,and controlling the flame temperature and combustor temperature profilealso prevents the formation of NO_(x), and favors the completeconversion of burning fuel to CO₂, minimizing CO production.

The present invention also utilizes high pressure ratios as a way ofincreasing efficiency and horsepower while simultaneously loweringspecific fuel consumption (“SFC”). When water is injected and convertedinto steam in the combustion chamber of the present invention, itacquires the pressure of the combustion chamber. It should be noted thatthe pressure of the combustion chamber is acquired by the steamirrespective of the pressure ratio of the engine. Thus, a higherpressure ratio can be obtained in the engine without expendingadditional work for performing compression for new steam or waterinjection. Because of the injection of massive amounts of water in thepresent invention, there is no need to compress more air than needed forcombustion, this excess air typically used in prior art systems forcooling. The elimination of this requirement results in an enormousenergy savings to the system and a significant increase, withoutadditional consumption of fuel, in the available shaft horsepowerwithout increasing turbine speed.

Water injection, as taught in the present invention, provides severaladvantages over the prior art. First, a minimal amount of additionalwork is required to pressurize water above the combustion chamberpressure. In steam injection system significant work must be expended toraise the steam to a pressure above that of the combustion chamber.Likewise, excess air requires additional work be expended to raise thefeed air to higher pressures to produce additional working fluid mass.Furthermore, when water is injected and converted to steam in thepresent invention, it acquires the pressure of the combustion chamberwithout additional work. This steam also has constant entropy andenthalpy.

In the present invention excess (waste) heat from combustion is used toconvert injected water to steam, thus increasing the working fluidpressure and mass of the working fluid without mechanical compression ofexcess air. In contrast, in a typical Brayton Cycle Turbine, 66%-75% ofthe mechanically compressed air is used to dilute the products ofcombustion in order to reduce the temperature of the working fluid tothe desired Turbine Inlet Temperature (“TIT”).

The steam generated by vaporization of the injected water can at leastdouble the mass of the combustion generated working fluid and increasethe net horsepower by 15% or more. Therefore, the water can be seen toserve as a fuel in this new thermodynamic system because it suppliespressure, mass, and energy to the system, resulting in an increasedefficiency of the present system.

The cycle of the present invention may be open or closed with respect towater. That means that the air and water may be exhausted (open) orrecovered and recycled (closed). Desalination or water purification canbe a byproduct of electric power generation from a stationaryinstallation or water borne ships, where the cycle is open as to air butclosed as to the desalinated water recovery. Marine power plants,industrial applications, drinking water and irrigation water clean upand recovery systems are also viable applications.

The present cycle can also be employed in the closed cycle phase inmobile environments, e.g. autos, trucks, buses, rail locomotives, marinecraft, commuter aircraft, general aviation and the like.

SUMMARY OF THE INVENTION

One of the objectives of this invention is to provide a new,thermodynamic power cycle, which can operate in an open or closed mode,that compresses a stoichiometric amount of air and combusts fuel withthe air so as to provide efficient, clean, pollution free power.

It is also an object of this invention to completely control thetemperature of combustion within a combustor through the employment ofthe latent heat of vaporization of water without the necessity tomechanically compress excess (dilution) air for cooling.

A further object of this invention is to reduce the air compressor loadin relation to a power turbine used in the engine so that a smallercompressor can be used and slow idling and faster acceleration can beachieved.

A further object of this invention is to separately control the turbineinlet temperature (TIT) on demand.

Another object of this invention is to vary the composition andtemperature of the working fluid on demand.

It is also an object of this invention to provide sufficient dwell timeof the reactants in the combustion chamber to permit stoichiometriccombustion, chemical bonding, and time for complete reaction andquenching, resulting in chemical equilibrium.

It is also an object of this invention to combust and cool the productsof combustion in a manner which will prevent the formation of smogcausing components such as NO_(x), unburned fuel, CO, particulates, CO₂dissociation products, etc.

It is also an object of this invention to provide a combustion systemwith 100% conversion of one pound of chemical energy to one pound ofthermal energy.

It is also an object of this invention to operate the entire powersystem as cool as possible and still operate with good thermalefficiency.

It is also an object of this invention to provide a condensing processin order to cool, condense, separate, and reclaim the steam ascondensed, potable water.

It is also an object of this invention to provide an electric powergenerating system which uses nonpotable water as its coolant andproduces potable water as a byproduct of the electric power generation.

It is also an object of this invention to provide a new cycle whichalternatively provides a modified Brayton cycle during one mode ofengine operation, a vapor air steam cycle during a second mode of engineoperation and a combined cycle during a third mode.

It is also an object of this invention to provide a combustor for usewith any turbine power generating system such that the power systemproduces electrical energy at a greater efficiency and reduced specificfuel consumption when compared with currently available systems usingcurrently available combustors.

It is also an objective of this invention to provide a combustor whichcan be retrofit into current hydrocarbon fuel burning systems replacingcurrently used combustors and eliminating the need for pollutionabatement equipment (catalytic converts, reburns, scrubbing systems)while increasing operating efficiency and decreasing pollution inexhaust streams.

It is also an object of the invention to provide a turbine powergeneration system which provides significantly increased usable shaftpower (net usable power) when compared with a Brayton cycle systemburning an equivalent amount of fuel.

It is also an object of this invention to provide a power generatingsystem which produces electrical energy at an overall efficiencysignificantly greater than 40%.

It is also an objective to provide a power generating system which burnshydrocarbon fuels in a more efficient manner to produce less green housegases (CO₂).

It is also an objective to efficiently provide large quantities of steamat any temperature and pressure desired.

In accordance with one exemplary embodiment of the present invention,referred to as the VAST cycle, an internal combustion engine isdescribed. This engine includes a compressor configured for compressingambient air into compressed air having a pressure greater than or equalto six atmospheres, and having an elevated temperature. A combustionchamber connected to the compressor is configured for staged delivery ofcompressed air from the compressor to the combustion chamber. Separatefuel and liquid injection controls are used for injecting fuel andliquid water respectively into the combustion chamber as needed andwhere needed. The amount of compressed air, fuel and water injected thepressure of the compressed air, fuel and water injected, the temperatureof the compressed air and fuel injected, and the temperature of theinjected water and the point of injection into the combustor are eachindependently controlled. As a result, the average combustiontemperature and the fuel to air ratio (F/A) can also be independentlycontrolled. The injected fuel and a controlled portion of the compressedair are combusted, and the heat generated transforms the injected waterinto a vapor. When the injected water is transformed into a vapor thelatent heat of vaporization of the water reduces the temperature of thecombustion gases exiting the combustor. An amount of water significantlygreater than the weight of the combusted fuel is used. However, the massof air feed to the system is significantly reduced. As a result, themass flow of combustion generated working fluid may be varied from 50%to greater than 200% of mass flows in current systems using the sameamount of fuel under most operating conditions.

A working fluid consisting of a mixture of a small amount of theunburnable 79% non-oxygen components of the compressed air, fuelcombustion products and water vapor is thus generated in the combustionchamber during combustion at a predetermined combustion temperature andcombustor temperature profile. Substantially all of the temperaturecontrol is provided by the latent heat of vaporization of the water. Anyexcess is provided only to assure complete combustion and is notprovided for cooling purposes. This working fluid can then be suppliedto one or more work engines for performing useful work. Alternatively,the working fluid, which is high temperature, high pressure steam can beused directly, such as injection in oil wells to increase flow, as aheat source for distillation towers or other equipment which utilizesteam for operation.

In more specific embodiments of the present invention, an ignitionsparker is used to start the engine. The engine may also be operatedeither open or closed cycle; in the latter case, a portion of theworking fluid exhaust may be recuperated. The flame temperature andcombustion chamber temperature profile are monitored using temperaturedetectors and thermostats located throughout the combustor.

Further, a computerized feedback control system may be used to monitorthe gaseous components of the exhaust stream and operating conditionsand feed rates can be automatically adjusted to minimize NO_(x) and COin the exhaust.

When the present invention is used, the combustion temperature isreduced by the combustion control means so that stoichiometriccombustion and chemical reaction equilibrium are achieved in the workingfluid. All chemical energy in the injected fuel is converted duringcombustion into thermal energy and the vaporization of water into steamcreates cyclonic turbulence that assists molecular mixing of the fueland air such that more complete combustion is effectuated. The injectedwater absorbs all the excess heat energy, reducing the temperature ofthe working fluid to the maximum desired operating temperature of thework engine. When the injected water is transformed into steam, itassumes the pressure of the combustion chamber, without additional workfor compression and without additional entropy or enthalpy. The carefulcontrol of combustion temperature prevents the formations of gases andcompounds that cause or contribute to the formation of atmospheric smogand, by virtue of the increased operating efficiency, reduces the amountof green house gases generated per usable energy produced.

In another embodiment of the present invention, electric power isgenerated using nonpotable water as its coolant, potable water beingproduced as a byproduct of the power or steam generation.

In a third embodiment of the present invention (a new cycle) the enginecan operate in three different modes. When the engine is operated inexcess of a first predetermined rpm (i.e. at a high RPM), waterinjection and the amount of compressed air combusted is kept constant asengine rpm increases. At an interim RPM, i.e. between a first (high) andsecond (low) predetermined rpm, the water to fuel ratio is increased asthe amount of excess air is decreased. When the engine is operated atvarious speeds below a second predetermined rpm (i.e. a low RPM), theratio of injected water to fuel is held constant and the amount ofcompressed air combusted is held constant, excess air beingsubstantially eliminated.

The use of this new cycle results in increased horsepower at a lowerrpm, slow idle, fast acceleration and combustion of up to 95% of thecompressed air at low rpm.

A more complete understanding of the invention and further objects andadvantages thereof will become apparent from a consideration of theaccompanying drawings and the following detailed description. The scopeof the present invention is set forth with particularity in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a vapor-air steam turbine engine inaccordance with a present invention;

FIG. 2 is a schematic diagram of a preferred combustor;

FIG. 3 is a cross-sectional view along line 3-3 of FIG. 2.

FIG. 4 is a block diagram of a vapor-air steam turbine engine thatincludes means for recovering potable water in accordance with thepresent invention;

FIG. 5 is a schematic drawing of one embodiment of the vapor-air steamturbine engine shown by a block diagram in FIG. 4.

FIG. 6 is a schematic drawing of a second embodiment of a vapor-airsteam turbine engine with potable water recovery capabilitiesincorporating features of the invention.

FIG. 7 is a graph showing the effect of pressure ratio on thermalefficiency for the vapor-air steam turbine engine of FIG. 1.

FIG. 8 is a graph showing the effect of pressure ratio on specific fuelconsumption for the vapor-air steam turbine engine of FIG. 1.

FIG. 9 is a graph showing the effect of pressure ratio on turbine powerfor the vapor-air steam turbine engine of FIG. 1.

FIG. 10 is a graph showing the effect of pressure ratio on net power forthe vapor-air steam turbine engine of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A. Basic Configuration Of The Present System

Referring now to FIG. 1, there is shown schematically a gas turbineengine embodying the teachings of the present invention. Ambient air 5is compressed by compressor to a desired pressure resulting incompressed air 11. In a preferred embodiment, compressor 10 is a typicalwell-known two or three stage compressor, and the ambient air iscompressed to a pressure greater than about four (4) atmospheres, andpreferably 10 to 30 atmospheres. The temperature of the compressed airdepends on the compression ratio. Al a compression ratio of 30:1 thecompressed air temperature is approximately 1424° R (964° F.).

The flow of the compressed air 11 is controlled by an air flowcontroller 27 to a combustor 25. Combustors are well-known in the art.However, in the present invention, the compressed air 11 is supplied ina staged, circumferential manner by air flow control 27 to the combustor200 shown in FIG. 2 and more fully described below. The staged feed ofthe air allows controlling and limiting of combustion temperature (flametemperatures) throughout the combustion chamber 25. The normally highpeak temperatures are reduced while still generating the same totalenergy output from the combustion.

Fuel 31 is injected under pressure by fuel injection control 30. Fuelinjection control is also well-known to skilled artisans. The fuelinjection control 30 used in the present invention can consist of aseries of conventional single or multiple fuel feed nozzles. Apressurized fuel supply (not shown) is used to supply fuel, which can beany conventional hydrocarbon fuel, such as diesel fuel #2, heating oil,preferably sulfur free, well head oil, propane, natural gas, gasolineand alcohols such as ethanol. Ethanol may be preferable in someapplications because it includes or can be mixed with at least somewater which may be used for cooling combustion products, thus reducingthe requirement for injected water. Also ethanol water mixtures have amuch lower freezing point thus increasing the ability to use the enginein climates which have temperatures below 32° F.

Water 41 is injected under pressure and at a preset but adjustable rateby a pump controlled by water injection control 40 and may be atomizedthrough one or more nozzles, into the feed air stream, downstream ofcombustion into combustion chamber 25 or into the flame if desired asexplained further below.

The temperature within combustor 25 is controlled by combustioncontroller 100 operating in conjunction with other elements of thepresent invention detailed above. Combustion controller 100 may be aconventionally programmed microprocessor with supporting digital logic,a microcomputer or any other well-known device for monitoring andeffectuating control in response to feedback signals from monitorslocated in the combustion chamber 25, the exhaust stream 51 (expandedworking fluid 21) or associated with the other components of the presentsystem.

For example, pressure within combustor 25 can be maintained by aircompressor 10 in response to variations in engine rpm. Temperaturedetectors and thermostats 260 (only one is shown for clarity) withincombustor 25 provide temperature information to combustion control 100which then directs water injection control 40 to inject more or lessliquid water as needed. Similarly, working fluid mass is controlled bycombustion control 100 by varying the mixture of fuel, water and aircombusted in combustor 25.

There are certain well-known practical limitations which regulate theacceptable maximum combustion temperature. Foremost among theseconsiderations is the maximum turbine inlet temperature (TIT) which canbe accommodated by any system. To effectuate the desired maximum TIT,water injection control 40 injects water as needed to the working fluid21 to keep the combustion temperature within acceptable limits. Theinjected water absorbs a substantial amount of the combustion flame heatthrough the latent heat of evaporation of such water as it is convertedto steam at the pressure of combustor 25.

For ignition of the fuel injected into combustor 25, a pressure ratio ofgreater than 12:1 is needed to effectuate self-compression ignition.However, a standard ignition sparker 262 can be used with lower pressureratios.

As mentioned above, combustion controller 100 independently controls theamount of combusted compressed air from air flow control 27, fuelinjection control 30, and water injection control 40 so as to combustthe injected fuel and substantially all of the oxygen in the compressedair. At least 95% of oxygen in the compressed air is combusted. If lessthan 100% of the O₂ is combusted then sufficient O₂ is available tocomplete stoichiometric bonding and for acceleration. When 100% of theair is consumed in the combustion process, forming CO₂, no oxygen isavailable to form NO_(x). The heat of combustion also transforms theinjected water into steam, thus resulting in a working fluid 21consisting of a mixture of compressed, non-combustible components ofair, fuel combustion products and steam being generated in thecombustion chamber. Pressure ratios from about 4:1 to about 100:1 may besupplied by compressor 10. TIT temperatures may vary from 750° F. to2300° F. with the higher limit being dictated by materialconsiderations. However, a higher TIT can be provided if the turbine isfabricated from materials, such as ceramics or other refractorymaterials, which can resist higher temperatures.

A work engine 50, typically a turbine, is coupled to and receives theworking fluid 21 from combustion chamber 25 for performing useful work(such as by rotating a shaft 54 for example) which, in turn, drives aload such as a generator 56, which produces electric energy 58, or theair compressor 10. While the present invention discusses the use of aturbine as a work engine, skilled artisans will appreciate thatreciprocating, Wankel, cam or other type of work engines may be drivenby the working fluid created by the present invention.

Because of pressure differences between the combustor 25 interior andthe turbine exhaust, the working fluid expands as it passes by workengine 50. The expanded working fluid 51 is exhausted by exhaust control60 at varying pressure, generally from 0.1 atmospheres to about 1 atm.depending on whether a closed cycle with vacuum pump or open cycle isused. However, higher exhaust pressures are possible. Exhaust control 60may also include a heat exchanger 63 and/or condenser 62 for condensingthe steam 61 from the expanded working fluid 51 as well as arecompressor 64 for exhausting the expanded working fluid 51. The steamcondensed in condenser 62 exits as potable water 65.

FIG. 2 shows a schematic diagram of a preferred combustor 200, whichincorporates features of the invention, having an inlet end 198 and anexhaust end 196. In the embodiment shown the combustor comprises threeconcentric stainless steel tubes 202, 206, 210 and inlets for air, waterand fuel. The inner tube 202 is the longest of the tubes, the middletube 206 is the shortest tube and the outer tube 210 is of anintermediate length. The inner or central tube 202, in a particularembodiment, has an inner diameter of 5 inches and a wall thickness ofabout ½″. There is approximately a one inch air flow space between eachof the inner tube 202, the middle tube 206 and the outer tube 210 (theinner air flow space 204 and the outer air flow space 208,respectively). The inlet end of the middle tube 206 and the outer tube210 each have a hemispheric head 224, 226 connected to the circumferenceof each respectively to form a closed space 228, 230 contiguous with thespace between the tubes 204, 208, creating a flow path, as describedbelow, from the exterior of the combustor 200, through the space betweenthe outer tube 210 and middle tube 206 (the outer air flows space 208)and then between the middle tube 206 and the inner tube 202 (the innerair flow space 204) and through burner 214.

Covering the inlet end or head 212 of the inner tube 202, as shown inFIG. 3, is an air feed plate 232 to which are attached nested tubeswhich comprise the burner 214. Burner 214 is formed by three concentrictubes with the inner fire tube 216 being 2 inches in diameter, thecentral fire tube 218 being about 3 inches in diameter and the outerfire tube 220 being about 4 inches in diameter. The fire tubes 216, 218,220 are progressively longer in length so that a straight lineconnecting the internal ends thereof form a flame containment cone 222with an angle of the cone 222 being from about 50 to 90 degrees.

The inlet end of the central fire tube 216 extends into the air feedchamber 228 formed between the hemispheric head 224 on the middle tube206 and the inlet end of the central tube 202. As shown in FIG. 3, asecond air feed plate 236 with holes 234 therein covers the inlet end ofthe inner fire tube 216. In addition, holes 234 are distributed aroundand through the periphery of the outer surface of the inner fire tube216 where it extends into the air feed chamber 228. Centrally locatedand passing through the hemispheric heads 224, 226 and the second airfeed plate 236 is a fuel injection nozzle 218 positioned to deliver fuelfrom the exterior of the combustor 200 into the inlet end of other innerfire tube 216 where the fuel is mixed with the air passing into theinner fire tube 216.

Air for combustion is fed at the desired pressure through one or moreair inlets 240 in the outer hemispheric head 226. The air then flowsalong the outer air flow space 208 between the middle tube 206 and outertube 210 from the inlet end 198 to the exhaust end 196 where it impingeson the exhaust end plate 242 which joins, in a leak proof manner, theexhaust end 196 of the outer tube 210 to the outer surface of the innertube 202. It then flows through the inner air flow space 204 back to theinlet end 198 where the air, now further heated by radiant energy fromthe outer surface of inner tube 202, enters the air fed chamber 228 forfurther distribution through the holes 234 and into the burner 214.

The ratio of air flowing into and through the respective portions of theburner is defined by the respective areas of the holes 234 into thoseareas. As best shown in FIG. 3, the number of holes 234 and crosssectional area of each hole is chosen, in one preferred embodiment, sothat holes 234 in the second air feed plate 236 and side wall of theinner fire tube 216 comprise 50% of the hole area, which feeds the firstfire zone 250, and the holes in the air feed plate feeding the spacebetween the inner fire tube 216 and the inlet end of the central tube202 constitutes the remaining 50% distributed so that 25% of the openarea is in the holes 234 in the air feed plate over the space betweenthe inner fire tube 216 and the middle or central fire tube 218, feedingthe second fire zone 252, 12.5% of the open area is through the holes234 into the space between the middle fire tube 218 and the outer firetube 220, feeding the third fire zone 254, and the remaining 12.5% ofthe open area is through the holes 234 into the space between the outerfire tube 220 and the inner tube 202, feeding the fourth fire zone 256.

Accordingly, a defined amount of fuel is fed through the fuel nozzle 218directly into the first fire zone 250. A stoichiometric amount of air,or a slight excess, at the desired combustion pressure, and having anelevated temperature heat generated as a result of compression and, ifdesired, countercurrent heat exchange with hot gases exiting thecombustor, is fed into the closed space 230. The air flows through theouter air flow space 208 and the inner air flow space 204 where it picksup further heat radiated from the inner tube 202 once combustion isinitiated. This now further heated air is distributed through the holesso that the fuel is burned with oxygen in 50% of the air feed whichenters the first fire zone 250. As the oxygen starved flame enters thesecond fire zone 252 an additional amount of oxygen in the next 25% ofthe air is consumed; likewise, oxygen in the next 12.5% of the air isconsumed by the flame in the third zone 254 and the oxygen in theremaining 12.5% of the air is consumed in the fourth fire zone 256,resulting in full, stoichiometric combustion entering the equilibrationchamber 258.

The temperature of the flame and combustion chamber temperature profileis monitored through thermocouples, or other temperature sensors 260located throughout the combustor. The locations of the temperaturesensors 260 in FIG. 2 are merely representative and may be in variousdifferent locations in the center and on the walls of the tubes asrequired.

In order to control the temperature of the flame and the temperatureprofile in the combustion chamber liquid water (not steam) is injectedthrough water nozzles 201 into the combustor at several locations. FIGS.2 and 3 show several water nozzles 201 which are used to transfer theliquid water from the exterior of the combustor into the equilibrationchamber 258 of the combustor. As best shown in FIG. 2, several sets ofwater nozzles 201 are placed along the length of the combustor. In apreferred embodiment at least three sets of nozzles 270, 272, 274 areused and each set includes three nozzles 201 with the three nozzles 201being only in less than about 180° of the circumference and at least twoof the sets being in a different 180° of the circumference to cause amixing flow, and possibly a vortex flow, in the working fluid passingalong the length of the equilibration chamber 258. While the nozzles areshown to be radial to the combustor inner tube 202, to create moreturbulence as the water enters the equilibrium chamber, flashes to steamand expands, the nozzles may be placed at any number of different anglesto the central axis of the combustor to create more tangential flow orto direct the injected material down stream. The water control 40, incoordination with control valves (not shown) on each of the nozzles 201or each set of nozzles 270, 272, 274 controls the amount and location ofwater introduced through the respective nozzles 201 into theequilibration chamber 258 and, in turn the temperature at specific spotsin the chamber 258 and the temperature profile therein. Under normaloperating conditions less than all of the nozzles 201 may be injectingwater at any time. FIG. 2 also shows at least one water nozzle 201 forproviding water to the air feed chamber 228 to add steam to the airprior to said air being reacted with the fuel. Further, additionalnozzles may feed water into the inner or outer air flow space 204, 208.The ultimate objective, which has been demonstrated by actual operationof the combustor is to limit the temperature in the equilibrationchamber 258 and the fire zones 250, 252, 254, 256 to not greater thanabout 2200° F. to 2600° F. thus preventing or significantly limiting theformation of NO_(x) while providing sufficient residence time at aboveabout 1800° F. to allow complete conversion of the burning fuel to CO₂.Additionally, more water nozzles may be added further down stream asdesired to add additional water if, for example it is desired to feed asteam turbine rather then a gas turbine or the ultimate objective is toproduce large quantities of high pressure, high temperature steam. Insuch instances, water to fuel ratios as high as 16 to 1 have beendemonstrated without effecting the flame stability or generatingpollutants.

While the fuel injected into the combustor will spontaneously igniteonce the internal components of the combustor are hot, it is initiallynecessary, when starting a cold combustor, to provide a ignition sparkto initiate the flame. This is provided by igniter 262 located in thefirst fire zone 250. FIG. 3 shows two igniters 262. However, it has beenshown that a single igniter is adequate. The igniter 262 is typically aspark plug such as is used in high temperature aircraft engines.However, a glow plug, resistance heated high temperature metal rod or aspark ignited hydrogen flame are also suitable to institute ignition.One skilled in the art will readily identify alternative igniters.

The multiple tube construction of the combustor provides a uniquebenefit regarding the mechanical stress applied across the central tube202 during operation. In the preferred embodiment discussed above, theworking fluid in the space within the inner tube 202 (the equilibrationchamber 258) is at elevated temperatures, possibly as high as 2600° F.,and pressures from about 4 atmospheres to greater than 30 atmospheres.Generally, if a means were not provided to lower the temperature of thewall of inner tube 202 or prevent the inner tube 202 from experiencing asignificant differential pressure across that wall, these operatingconditions could damage the material used to construct the tube.However, as shown in FIG. 2, the air exiting the compressor 10 entersthe outer air flow space 208 at a pressure substantially the same as thepressure within the inner tube 202. Substantially the same pressureexists within the inner air flow space 204. As a result, the centraltube 202, with the exception of its exhaust end 196, for all practicalpurpose does not have a differential pressure applied thereto. Further,the compressed air flowing through the inner air space 204 continuouslysweeps across the entire outer surface of the inner tube 202, thuskeeping the inner tube outer diameter at a temperature less than that ofthe working fluid flowing in the equilibration chamber 258. The onlytube exposed to the full differential pressure, ie, the pressuredifference between the internal pressure in the combustor andatmospheric pressure, is the outer tube 210 which is at the lowesttemperature of the three tubes and is most capable of withstanding thedifferential pressure. This design is so effective in keeping the outertube 210 at the lowest possible temperature that if room temperaturecompressed air is feed to the combustor operating at a TIT of 2100° F.the outer tube 210 is cold to the touch during operation.

The pressure ratio, turbine inlet temperature, and water inlettemperature can be varied as required by the application in which theVAST cycle is used. Additionally, the fuel/air ratio is changeddepending on the type of fuel used, to assure stoichiometric quantities,and the efficiency of systems using the combustor can be increased byuse of more efficient compressor and turbine designs. Increasing the airfeed while maintaining the fuel/air ratio constant results in aproportional increase in the power output.

The VAST cycle is a combination of a compressed air work cycle and asteam cycle since both air and steam are present as a working fluid.Each makes up a portion of the total pressure developed in thecombustor. In the present discussion, it will be understood that theterm working fluid is intended to include the steam generated frominjected water products of the fuel burned with the oxygen in the inletcompressed air together with the nonburnable air components and anyexcess compressed air which may be present, and thus includes all of theproducts of combustion, inert air components and steam. The term “steam”refers to water which is injected in the liquid state to becomesuperheated steam. The described process makes use of the combinedsteam, combustion products and air as a working fluid.

A brief discussion of the thermodynamic processes in the VAST cycle nowfollows. The air is compressed in compressors, generally a two or threestage compressor, 10. The exit conditions at the outlet of compressor 10are calculated using isentropic relations for compression and the realconditions are calculated using a compressor efficiency of 85%.

As explained above, compressed air enters combustion chamber 25 throughair flow control 27.

The combustion chamber 25 burns fuel at constant pressure underconditions also approximating constant temperature burning. Thetemperature is completely controllable since there are independent fuel,air and water controls. Compressed air input to the combustor, afterstart-up, is at constant pressure. Thus, the combination of the air feedat a constant pressure and a fixed fuel/air ratio in combination withcontrol of the TIT by water injection results in a constant pressure inthe combustion chamber. Burning occurs in the combustor immediatelyfollowing injection of fuel under high pressure and provides idealizedburning conditions for efficiency and avoidance of air contaminants inwhich the fuel mixture may at first be richer than the mixture forcomplete combustion, additional air being added as burning continues,this air being added circumferentially around the burning fuel and in anamount which, as a minimum, equals the amounts necessary for completecombustion (a stoichiometric amount) but can ultimately exceed thatnecessary for complete combustion of the fuel components. While astoichiometric amount of air may be introduced a 5% excess appears toforce complete combustion and provides excess oxygen for acceleration ifdesired.

Water at high pressure, which may be as high as 4000 psi or greater, isinjected by water injection control 40. The pressure is maintained at alevel to prevent vaporization prior to entering the combustor. Due tothe high temperatures and lesser pressure in the combustion chamber 25,the injected water is instantaneously flashed into steam and mixes withthe combustion gases. The amount of water that is added into thecombustion chamber 25 depends on the desired turbine inlet temperature(TIT) and the temperature of the water just prior to injection. Part ofthe heat released during the combustion of fuel is used to raise thetemperature of the unburned (inert) portion of the compressed air fromthe three stage compressor 10 to the TIT. The remaining heat ofcombustion is used to convert the injected water into steam.

Table 1 sets forth several sets of operating conditions for a systemusing #2 diesel fuel. For example referring to Example 30, a pressureratio of 30/1, a turbine inlet temperature of 2050° F., a turbine outletpressure of 0.5 atmosphere and a water inlet temperature of 598° F. areindicated. The results predicted by a computer simulation modeling thesystem projects the efficiency of the compressor and the work engineusing a fairly standard published turbine efficiency of 92%. Thisresulted in a net horsepower of 760, an SFC of 0.31 and an efficiency of0.431. The examples calculated in Table 1 of a simulated process andlisted in the data tables show the result of varying the pressure ratio,water inlet temperature and Turbine Inlet Temperature (TIT) heldconstant.

In a like manner, other operating conditions can be varied. For examplethe water temperature can be increased, the maximum temperature beingnot greater than the desired TIT. Preferentially, the water temperatureis not increased to a temperature greater than about 50° F. below thedesired TIT. However, for practical reasons, since the working fluidexiting the turbine is used to heat the feed water, the inlet water isusually held to no more than about 50° F. below the turbine exittemperature. The higher the water temperature the greater the quantityof water necessary to reduce the combustion temperature to the TIT, thusresulting in a greater mass of gases flowing to the turbine and agreater power output. Likewise the TIT can be raised or lowered.Examples 1-7 in the data table were calculated at a TIT equal to 1800°F. This is the generally accepted maximum for turbines which do notutilize high temperature alloys or hollow blade cooling with either airor steam. However, utilization of high temperature and/or corrosionresistant alloys, high temperature composites, ceramics and othermaterials designed for high temperature operation, such as used inturbine jet engines will allow operation at 2300° F. or higher. Examples8-13, 15-31, and 14 illustrate operation at more elevated temperatures,namely 2000° F., 2050° F. and 2175° F. respectively.

Examples 1-5 of Table 1 show the effect on horsepower, efficiency andSFC by increasing the air compression ratio. The effect of reducing theexit pressure (calculated at a turbine efficiency and compressorefficiency of 85%) is shown in Examples 2, 6 and 7. Examples 8-13 showthe effect of air compression ratio on a system with a TIT of 2000° F.,a turbine exit pressure of 0.5 atmosphere and a H₂O inlet temperature ofabout 595 to about 700° F. when calculated at an assumed turbineefficiency of 90%. It should be noted that a turbine efficiency of 93%is claimed by currently available air compression axial turbines and thepower turbine expander train.

Examples 15-24 and 25-31 further demonstrate the effect of increasingair pressure at two different turbine efficiencies.

In examples 1 through 31, the fuel is diesel #2 and the fuel to airratio is 0.066, which is the stoichiometric ratio for #2 diesel fuel.With other fuels a different f/a ratio is required to maintainstoichiometric conditions. Example 32 uses methane and a f/a=0.058.Because methane burns more efficiently than diesel fuel, less fuel perpound of air is used and, as a result, less water is added.

TABLE 1 VAST CYCLE F/A = 0.660 Air Comp. Turb. Eff. H₂O Temp TIT Turb.Exit Turb Open Cycle Closed Cycle Ex. Ratio % ° F. ° F. Press, atmos HPHP Eff SFC HP Eff. SFC 1 10:1 85 502 1800 1.0 722 517 .292 .459 517 .292.459 2 22:1 85 566 1800 1.0 891 582 .328 .408 534 .301 .445 3 30:1 85631 1800 1.0 947 590 .333 .403 542 .305 .439 4 40:1 85 594 1800 1.0 998592 .334 .401 544 .307 .436 5 50:1 85 564 1800 1.0 1036 591 .333 .402543 .306 .438 6 22:1 85 595 1800 0.5 978 669 .377 .377 549  309  433 722:1 85 512 1800 0.25 1047 738 .416 .322 520 .293  457 8  5:1 90 7022000 0.5 770 649 .366 .366 515 .290 .461 9 10:1 90 702 2000 0.5 966 775.437 .307 661 .372 .360 10 15:1 90 681 2000 0.5 1041 803 .452 .296 691.389 .344 11 20:1 90 650 2000 0.5 1091 816 .460 .291 706 .398 .337 1225:1 90 621 2000 0.5 1128 822 .463 .289 712 .402 .334 13 30:1 90 5952000 0.5 1158 826 .465 .288 716 .403 .332 14 29:1 90 663 2175 0.5 1242914 .515 .260 805 .454 .295 15  5:1 85 700 2050 0.5 730 601 .339 .395439 .248 .541 16 10:1 85 700 2050 0.5 918 715 .403 .333 587 .331 .404 1715:1 85 700 2050 0.5 1026 771 .434 .308 663 .373 .359 18 20:1 85 6852050 0.5 1081 786 .443 .302 665 .375 .357 19 25:1 85 670 2050 0.5 1123795 .448 .299 674 .380 .353 20 30:1 85 651 2050 0.5 1154 797 .449 .291675 .381 .352 21 35:1 85 633 2050 0.5 1180 797 .449 .298 676 .381 .35222 40:1 85 617 2050 0.5 1202 797 .449 .298 676 .381 .352 23 45:1 85 6022050 0.5 1222 796 .448 .299 675 .380 .352 24 50:1 85 588 2050 0.5 1239794 .447 .299 672 .379 .353 25  5:1 92 700 2050 0.5 785 667 .376 .356529 .298 .449 26 10:1 92 700 2050 0.5 984 798 .450 .298 695 .392 .342 2715:1 92 685 2050 0.5 1078 845 .476 .281 737 .416 .322 28 20:1 92 6552050 0.5 1128 860 .484 .276 753 .424 .316 29 25:1 92 625 2050 0.5 1166868 .489 .274 762 .430 .312 30 30:1 92 598 2050 0.5 1195 872 .491 .273760 .431 .310 31 35:1 92 574 2050 0.5 1221 874 .493 .272 769 .433 .30932 29:1 93 664 2175 0.5 840 .475 .250

TABLE 2 BRAYTON CYCLE F/A = 0.02020 1# Air/Sec Air H₂O Turb. Exit Comp.Turb. Temp TIT Press, Turb Closed Cycle Ex. Ratio Eff. % ° F. ° F. atomsHP HP Eff SFC 33  5:1 92 2050 1.0 313 200 .369 .363 34 10:1 92 2050 1.0414 234 .431 .311 35 15:1 92 2050 1.0 466 239 .440 .304 36 20:1 92 20501.0 499 237 .436 .307 37 25:1 92 2050 1.0 523 231 .425 .315 38 30:1 922050 1.0 542 224 .413 .325 39 35:1 92 2050 1.0 557 216 .398 .336 40 40:192 2050 1.0 570 208 .384 .349

Example 32 is also calculated at a turbine efficiency of 93%, and aturbine inlet temperature of 2175° F. which are both claimed asoperating parameters of commercially available turbines (which do notuse the claimed invention.)

The effect of changing air compression ratio on the closed cycleperformance of the systems listed in examples 8-13, 15-20 and 25-30 areplotted on FIGS. 7-10. In particular FIG. 6 shows thermal efficiency,FIG. 7 shows SFC, FIG. 8 shows turbine power and FIG. 9 shows net power.

The combustor of the invention differs from prior devices in afundamental respect since the working fluid mass may be increased eitherat constant pressure, constant temperature or both. Constant temperatureis maintained by combustion controller 100 through controlled waterinjection by water injection control 40 in response to temperaturemonitors (thermostats) in combustor 25. Within combustor 25, typicalcombustion temperatures for liquid hydrocarbon fuels reach about 3,000°to 3,800° F. when a stoichiometric amount or a small excess ofcompressed air is supplied by compressor 10. Larger quantities of excessair reduce the resulting turbine inlet temperature but would not greatlyaffect the actual temperature of burning or the ignition temperature.

The practical limit of the discharge temperature from the combustor 25is in turn governed by the material strength of the containing walls atthe discharge temperature, the high temperature tolerance of thecombustor walls, the materials of construction of the power turbine, andwhether the turbine blades are separately cooled, either externally orinternally. This discharge temperature is controlled between suitablelimits by variation in the injection of high pressure water which thenflashes to steam, the heat of the vaporization and superheat beingequated to the heat of combustion of the fuel being burned. (Thetemperature of the burning fuel is reduced to the desired TIT primarilyif not totally by the heat of vaporization and superheat as the watervaporizes and then heats up to the TIT). The quantity of injected wateris thus determined by the desired operating temperature, being less forhigh superheats, but actually maintaining a fixed operating temperature.

The working pressure is kept constant by compressor 10 as required byany desired engine rpm.

The resulting working fluid mixture of combustion gases unreactedcomponents of air (i.e. N₂, CO₂) and steam is then passed into a workingengine 50 (typically a turbine as explained above) where expansion ofthe steam—gas mixture takes place. The exit conditions at the outlet ofworking engine 50 are calculated using isentropic relations and turbineefficiency.

The exhaust gases and steam from work engine 50 are then passed throughan exhaust control 60. Exhaust control 60 includes a condenser where thetemperature is reduced to the saturation temperature corresponding tothe partial pressure of steam in the exhaust. The steam in the turbineexhaust is thus condensed and may be pumped back into the combustionchamber 25 by water injection control 40. The remaining combustion gasesare then passed through a secondary compressor where the pressure israised back to the atmospheric pressure if a vacuum was pulled on theexit of the turbine so that it can be exhausted into the atmosphere.Alternatively, the exhaust from the turbine, which is a superheatedsteam stream, can be used directly, as will be recognized by thoseskilled in the art.

It can be seen that the present invention takes substantial advantage ofthe latent heat of vaporization of water. When water is injected into acombustion chamber, and steam is created, several useful results occur:(1) the steam assumes its own partial pressure; (2) the total pressurein the combustor will be the pressure of the combustion chamber asmaintained by the air compressor; (3) the steam pressure is withoutmechanical cost, except a small amount to pump in the water at pressure;(4) the steam pressure at high levels is obtained without mechanicalcompression, except the water, with steam at constant entropy andenthalpy. The water conversion to steam also cools the combustion gases,resulting in the pollution control described below.

B. Pollution and Efficiency Control

Any type of combustion tends to produce products which react in air toform smog, whether in engines or industrial furnaces, although ofdifferent kinds. The present invention reduces or eliminates theformation of pollution products in several ways discussed below.

First, internal combustion engines operated with cooled cylinder wallsand heads have boundary layer cooling of fuel-air mixtures sufficient toresult in small percentages of unburned hydrocarbons emitted during theexhaust stroke. The present invention avoids combustion chamber wallcooling in two distinct ways to keep the burning temperature for thefuel at a suitable level, both of which are shown in more detail in U.S.Pat. No. 3,651,641. First, hot compressed air is made to flow by airflow control 27 around an exterior wall of combustor 25 such thatcombustion occurs only within a small space heated above ignitiontemperatures. Second, the combustion flame is shielded with air unmixedwith fuel. Thus, a hot wall combustion, preferably above 2000° F., isutilized in an engine operating on the present cycle.

Next, smog products are also inhibited by operating the combustor withina defined temperature range. For example, CO and other products ofpartial combustion are reduced by high temperature burning, preferablywell above 2000° F., and by retaining such products for a considerabledwell time after start of burning. At too high a temperature, however,more nitrous and nitric oxides (NO_(x)) are formed. Accordingly, neitherextremely high nor extremely low temperatures are acceptable forreducing smog products. The combustion controller 100 in the presentinvention commences burning of the fuel and air at a controlled lowtemperature by the staged burning in the burner 214, then increasingprogressively for a considerable dwell time and then cools (aftercompletion of the burning) to a predefined, smog-inhibiting temperature(TIT) by the use of water injection. Thus, combustion is first performedin a rich mixture; then sufficient compressed air is added to allowcomplete combustion of the fuel with a minimum of excess oxygen and tocool the gases below about 2500° F. for about half of the dwell time inthe combustion chamber 25. Water injection is directly added to theburner, combustion chamber or upstream by water injection control 40 tomaintain an acceptable temperature preferably in the range of about2500° F. that assures complete burning of all the hydrocarbons beforecooling to the desired TIT.

In typical engines, hydrocarbon fuels are often burned in a mixture withair a little richer in fuel, i.e., at less than stoichiometricproportions in order to increase efficiency. This, however, results inexcess CO and more complex products of incomplete combustion. Thepresent invention, however, because it provides a progressive supply ofair through air flow control 27, dilutes the combustion and furtherreduces such smog products.

Oxides of nitrogen also form more rapidly at higher temperatures asexplained above, but can also be reduced by the controlled dilution ofthe combustion products with additional compressed air.

The present combustion cycle is compatible with complete and efficientfuel burning and eliminates incomplete combustion products and reducesother combustion products such as nitrogen oxides. Combustion controller100 allows burning of the combustion products at a considerable initialdwell time, after which the products of combustion and excess air arethen cooled to an acceptable engine working temperature, which may be inthe range of 1000° F. to 1800° F., or even as high as 2300° F. if propermaterials of construction are used in the turbine, or may be as low as700° F. to 800° F.

An equilibrium condition can be created by making combustion chamber 25at least about two to four times the length of the burning zone withincombustion chamber 25; however, any properly designed combustion chambermay be used.

A burning as described provides a method of reducing smog-formingelements while at the same time, providing a complete conversion of fuelenergy to fluid energy.

The VAST cycle is a low pollution combustion system because the fuel-airratio and flame temperature are controlled independently. The control offuel-air ratio, particularly the opportunity to burn all of the oxygenin the compressed air (or to dilute with large amounts of compressedair, if desired) inhibits the occurrence of unburned hydrocarbon andcarbon monoxide resulting from incomplete combustion. The use of aninert diluent (water) rather than air permits control of the formationof oxides of nitrogen and represses the formation of carbon monoxideformed by the dissociation of carbon dioxide at high temperature. Theuse of diluents of high specific heat, such as water or steam, asexplained above, reduces the quantity of diluent required fortemperature control. In the case of oxides of nitrogen, it should benoted that the VAST cycle inhibits their formation rather than, as istrue in some systems, allowing them to form and then attempting thedifficult task of removing them. The net result of all of these factorsis that the VAST cycle operates under a wide range of conditions withnegligible pollution levels, often below the limits of detection forhydrocarbons and oxides of nitrogen using mass spectroscopic techniques.

Others have attempted to inject small amounts of water but they havedone so under conditions not conducive to, or incompatible with,operation at zero pollution resulting in reducing efficiency.

Kidd U.S. Pat. No. 4,733,527 refers to the injection of relatively smallamounts of water into the combustion chamber at the same time as thefuel and apparently into the flame itself, thus reducing the temperatureof the flame in an attempt to reduce NO_(x) formation. However, Kidd, aswell as other persons skilled in the art, have been unable to obtainsignificant reduction of, or prevent the formation of, NO_(x). The bestNO_(x) levels that have been demonstrated by others on a combustor,without catalytic converters, is about 25 to 30 ppm. Kidd demonstratesthe best known prior art with control and reduction of NO_(x) levels tono less than 30 ppm by adding water in amounts equal to or less than theamount of fuel, ie WFR=1.0.

In contrast thereto applicant has actually demonstrated NO_(x) levels aslow as 4 ppm with a WFR of 5.57 when the compressed air inlettemperature was approximately 400° F. This is more fully set forthbelow. If the air temperature had been 964° F., which is the standardexhaust temperature from a 2 stage compressor at 30:1, the WFR wouldhave been 8.27. The ability to deliver such large amounts of water is aresult of operating a unique combustor, at conditions which everyone inthe past has said are inoperable and at which those skilled in the arthave said that unacceptable low temperatures would be created,combustion flame would be extinguished, and the operating efficiencywould render the equipment unusable as a power source for a work engine.Contrary to the prior art which operated to lower the flame temperatureon a system already using large amounts of air to control temperatures,applicant generates a controlled hot flame with a stoichiometric amountof air and then rapidly cools the combustion products to produce thedesired exhaust composition.

Substantially all of the cooling of the working fluid and/or thecombustion temperature and the exit temperature (the exit from thecombustor or turbine inlet temperature) is provided by the latent heatof vaporization of the injected liquid, such as liquid water. The resultis that the fuel/air mixture can be selected so that the most efficientflame from the standpoint of combustion, combustion products and heatgeneration can be selected and operation is not constrained by the need,as in prior art devices, to provide considerable excess air for coolingthe combustion products. Further, prior art devices, controlledpollutants by limiting the flame temperature. In contrast thereto thepresent invention allows a stoichiometric mixture (or nearstoichiometric) of air and fuel to be used to produce a hot staged flamewith complete combustion to eliminate CO residuals, followed bycontrolled cooling and mixing of the combustion products to the desiredTIT, the combination preventing the formation of NO_(x).

Further, one skilled in the art knows that the amount of power producedby a power turbine depends on the temperature and the mass of theworking fluid entering the turbine and the pressure difference acrossthe turbine. When a hot, efficient flame is produced by providing astoichiometric mixture of fuel and air (generally above 2300° F.) andsubstantially all cooling is provided by the latent heat of vaporizationof liquid water injected into the combustion chamber, the injectedliquid being used to reduce the exit temperature of the working fluid,to the maximum TIT for a state of the art gas turbines (1850° F. toabout 2100° F.) the amount of water is from about 5 to about 8 times theweight of fuel used, depending on the flame temperature and thetemperature of the compressed air and water entering the combustor. Fora specific flame, water, and air inlet temperature, the quantity ofwater supplied can be precisely determined for a desired TIT. While thegas turbine will operate in a highly efficient manner when the TIT ofthe working fluid in the 1850-2100° range, efficiency can be improved byusing a higher TIT. The current limiting factor is the materials ofconstruction of state of art turbines. Increasing the mass of theworking fluid entering the turbine while lowering its temperature byinjecting high volumes of water to produce the preferred TITsignificantly increases the efficiency of electrical energy productionby the turbine. This is accomplished by use of applicant's inventionwherein the excess air is substantially eliminated resulting in a hotflame. Rapid cooling to the preferred TIT by water injection results inimproved efficiency for the production of useful energy while at thesame time preventing the formation of undesirable pollutants such as NOand NO₂ due to the almost complete elimination of excess O₂ availablefor nitrogen oxidation.

Table 1 of the specification lists selected operating conditions andresults generated for 32 different operating conditions. In allinstances the efficiency is higher than, and the specific fuelconsumption is less than, prior art engines, operating with the sameamount of fuel. Table 2, Examples 33-40 show simulation results ofBrayton cycle engines operating with the same amount of air at anA/F=0.02020. Computer simulation has shown that the claimed engine willoperate 10% more efficiently, and the fuel consumption will be 10% lessthan engines operating without the claimed invention.

Actual operation of a combustor under conditions produced a workingfluid with NO_(x) and CO below 1 ppm and no unburned fuel (HC). 99-100%combustion efficiency was obtained. The combustor operated in a stablemanner (no evidence of flame instability or temperature fluctuation)with water/fuel ratios used for the examples set forth in Table 3.

Table 3 sets forth data obtained for a VAST Combustor fabricated andoperated in the manner described herein using diesel #2 as the fuel andunder conditions set forth in Example 3, 13, 20 and 30, with theexception that the exit pressure was 1.0 atmosphere.

TABLE 3 PRESS RATIO/HP 30:1/770 30:1/770 30:1/770 30:1/770 30:1/77030:1/770 30:1/770 30:1/770 AIR 1.2314 1.16 1.0586 1.1501 1.0918 1.08331.2159 1.1493 FUEL 0.0658 0.0655 0.0649 0.064 0.0661 0.066 0.066 0.0646A/F 18.71 17.71 16.31 17.97 16.52 16.41 18.42 17.79 H2O 0.4218 0.4090.3851 0.3233 0.4361 0.3481 0.3679 0.3655 # H2O/# FUEL 6.41 6.26 5.935.05 6.60 5.27 5.57 5.66 TIT 1891 1937 1953 2103 1979 2032 1895 1781EFFICIENCY-% 94.7 94.9 95.1 94.7 94.7 95.1 95.1 96.4 O2-% 4.3 3.9 3.62.4 2.4 3.3 3.6 3.6 NOX - PPM 23 8 8 7 5 7 4 6 CO - PPM 758 0 0 0 0 0 00 CO2-% 11 11.2 11.5 12.2 12.2 11.6 11.5 12.7 EX AIR- % 23 21 19 12 1318 19 68 COMBUSTIBLES-% 0.04 0.03 0.00 0.05 0.04 0.00 0.00 0.05

The exhaust gas was analyzed using an Enerac 2000, provided by EnergyEfficient Systems, calibrated for O₂, NO_(x), CO and combustibles(unburned fuel) by the supplier. The Enerac 2000 was then connected bycopper tubing to a test port located at the TIT position in thecombustor.

Listed in Table 3 are various operating parameters and gas compositionreadings. The values given for fuel, air and water are in pounds persecond. TIT corresponds to the turbine inlet temperature. Also includedare calculations of the air/fuel ratio and water/fuel ratio.

The 7 lines on the bottom half of Table 3 reflect values measured by theEnerac 2000 (NO_(x), CO, O₂, combustibles) and calculated values forburning efficiency, CO₂ and excess air. The manufacturer of the Enerac2000 has indicated that the burning efficiency is artificial low becausethe particular unit used is an older unit which does not have acorrection in the algorithm for measurement at ambient temperaturerather than recommended temperature of 200° F. The actual values ofburning efficiency rather than being from 94.4 to 96.4 are closer to100%. The manufacturer of the test equipment has indicated that themeasured values are much more reliable and that the readings of unburnedfuels indicate 99-100% combustion efficiency.

Depending on operating conditions in each test run, NO_(x) was below 9ppm and CO was undetectable with recorded NO_(x) levels as low as 4 ppmand observed readings on the digital readout of the test unit for otherdata points as low as 3 ppm.

While the water/fuel ratio for the illustrated test run was from 4.75 to6.88, water to fuel ratios as high as 9.36 were recorded withouteffecting the stable operation of the combustor. Further, input air wasapproximately 400-500° F. When the input temperature is greater than900° F., which is the typical temperature for a two stage compressorwith a 30 atmosphere exit pressure, at least an additional two pounds ofwater per pound of fuel is required to maintain the flame temperature inthe desired range.

The exhaust gases exiting the combustor, when operated under theconditions listed in Table 3 hereto with indication of 0 ppm of CO, whenvisibly observed, were completely clear and transparent with noobservable smoke, steam or particulate material. Aside from visualdistortion due to the heat of the exhaust stream, there was absolutelyno visible indication that diesel #2 fuel was being burned.

The combustor 25 represents a mechanism for using heat and water tocreate a high temperature working fluid without the inefficiencies thatresult when, in order to generate steam the heat is transmitted througha heat exchanger to a flash vaporizer or a boiler. The addition of waterrather than merely heated gas to the products of combustion represents ameans for using a fluid source for producing the gas, the water flashingto steam providing a very efficient source of mass and pressure and atthe same time giving tremendous flexibility in terms of temperature,volume, and the other factors which can be controlled independently. Inaddition, injected water, when added directly into the combustionchamber to quench the combustion process, greatly reduces contaminationthat results from most combustion processes.

Further, the amount of nitrogen available to form NO_(x) issignificantly reduced. Only about 30% as much nitrogen is in thecombusted gases of the combustion chamber 25 compared to a normal airdilution open cycle Brayton engine of any form or model because waterrather than excess air is used for cooling and the amount of air fed tothe system is thus greatly reduced. In particular, about ⅓ as much airis fed to the combustor. As discussed below this also significantlyreduces the energy expended on compressing the feed air.

Further, the injected water rapidly expands as it flashes to steam, thevolume increase at 30 atmosphere being greater than 50/1.

C. Water Injection

Water injection control 40 controls the pressure and volume of water 41injected through nozzles 201, arranged for spraying a fine mist of waterin the chamber. Water may be injected into the combustor in one or moreareas, including: atomized into intake air before compressor 10, sprayedinto the compressed air stream generated by compressor 10, atomizedaround or within the fuel nozzle or a multiplicity of fuel nozzles,atomized into the combustion flame in combustion chamber 25, or into thecombustion gases at any desired location, or downstream into thecombustion gases prior to their passage into work engine 50. Other areasof injection can be readily envisioned by the skilled artisan. Asdescribed earlier, the amount of water injected is based on thetemperature of the combustion products and the desired maximumtemperature and temperature profile in the equilibration zone 258 asmonitored by temperature sensors 260 in combustor 25. The amount ofwater injected is also dependent on the system using the VAST cycle. Forexample, if the water is recycled as for use in a motor vehicle, thewater is cooled as much as possible to obtain a usable balance betweentotal water used and power output, i.e., if the inlet water temperatureis low and the TIT is high a small volume of water can be used to reducethe combustion temperature to the TIT. On the other hand, if a majorpurpose of the system is to produce potable water from polluted or saltwater, as discussed below, while generating electrical energy, the waterinlet temperature would be raised as high as possible while the TIT islowered.

D. Increased Available Power

Using the VAST system with water injection, a stoichiometric amount ofair, or a slight excess of air, is fed. The amount of air fed issignificantly reduced, when compared with a system burning the samequantity of fuel operating according to the Brayton cycle (no waterinjection, cooling provided by excess air). The VAST system thusrequires a much smaller compressor then in a Brayton cycle combustorand, accordingly, that portion of the energy generated by the turbinewhich is used to drive the compressor is significantly reduced. Forexample, if about one-third of the Brayton cycle quantity of the air isused a smaller compressor with about one-third the power requirementscan be used. The energy which would have gone to power the largercompressor is instead now available as additional energy for supplyingthe customer or run additional equipment.

Examples 33-40 list calculated values for a power system operating underthe Brayton cycle. This data can be compared with Examples 25-31operating (at 1#/sec air) under the same conditions according to theVAST system. Off particular relevance is the significant difference inthe available turbine horsepower, a significant additional amount beingavailable from a system operating with the VAST combustor.

More specifically, using the fuel requirements from the NACA tables fordiesel #2, the Brayton cycle requires 0.0202 lbs/sec of diesel #2 foreach pound of air. However, stoichiometric requirement (no excess air,all fuel and oxygen consumed) are 0.066 pounds of diesel per pound ofair. In other words, when 0.0202 lbs of diesel are burned the oxygen inonly 0.306 pounds of air are consumed. For equal quantities of fuel,namely 0.066 lbs of diesel, VAST consumes 1 pound of air while a Braytoncycle system utilizes 3.27 pounds of air. However, the VAST combustorrequires 0.5463 pounds of water when operating at a TIT 2050° F. for atotal mass flow to the turbine of 1.6123 pounds compared to 3.336 poundsfor the Brayton cycle. Since the power output of the turbine depends onthe mass fed to the turbine. In order for the turbine to generate thesame amount of energy, the VAST combustor requires the total mass to beapproximately doubled (2.07 times) increasing all of the feed componentsproportionally and the amount of air to 2.07 pounds. Comparing this tothe 3.27 pounds required with Brayton, 1.2 pounds less air is required,a compressor of 63.3% of the size of the Brayton cycle is used and theenergy needed to drive the compressor to supply the required air isreduced by 36.7%. Diesel #2 releases 1936 BTU/pound when fullycombusted. It can then be calculated that 0.066 pounds of Diesel #2 whencombusted generates 1808 combusted horsepower. Example 30, operating at43.1% efficiency generates 766 hp. While Brayton operates at a lesserefficiency, assuming it operates at the same efficiency, the balance ofthe combusted horsepower is required to drive the compressor. Therefore,the compressor to deliver 3.27 pounds of air require 1042 hp or 318.65hp per pound of air. Therefore, for the same amount of fuel, it can becalculated that about additional 723 hp is available as additionalavailable shaft energy.

Another way of comparing the systems, if a current single shaftcompressor turbine were operated and the VAST combustor were used toreplace the combustor operating under the Brayton cycle sufficient massis generated to drive the turbine in the same manner as in the past.However, because additional fuel must be burned to consume all thedelivered oxygen and additional water added to control the temperatureof that additional burned fuel sufficient excess mass is generated atthe desired TIT to drive a second turbine at least about 50% in size ofthe first turbine, or a significant amount of additional highertemperature, high pressure steam is available for other powerapplications.

D. Other Embodiments Of Present Invention

1. Power Plant Including Water Purification

In the case of electric power generation using sea water, brackishwater, or polluted ground water or well water as a coolant, the cyclemay be open as to electric power, and the water used as shown in FIGS. 4and 5. Feed water 41, moved by pump 42, is heated as it passes throughcondenser 62 and heat exchanger 63 countercurrent to exiting hot workingfluid 51 and is flash vaporized in the combustor 25 or 200 as describedabove. By increasing the diameter of the combustion chamber the velocityof the working fluid can also be reduced thus allowing easier removal ofwater bourn materials or solutes.

The typical temperature of operation of the combustor is 1500° F. to2300° F. When salt water or brackish water is the feed source thistemperature is above the melting point but significantly below theboiling point of the salts in sea water (85% of sea salt is NaCl; anadditional 14% is composed of MgCl₂, MgSO₄, CaCl₂ and KCl). When thewater flashes to steam the dissolved inorganic contaminants rain out asa liquid and organic contaminants are combusted. For example, NaCl meltsat 1473° F. and boils at 2575° F., the other salts have lower meltingpoints and higher boiling points. As a result the molten salts arereadily collected along the bottom wall of the combustor and the liquidsalts can be removed by a screw assembly on the bottom of the combustor,fed through an extruder and die where it can be formed into rods orpellets, or sprayed through nozzles, using the pressure in the combustoras the driving force, into a cooling chamber where the waste materialcan be deposited in a waste collection container 80 as flakes, powder,or pellets of any desired size or shape by selection of the proper spraynozzle dimensions and configuration. Because the salt water is exposedto extremely high temperatures in the combustion chamber the saltrecovered is sterile and free of organic matter.

Water on the order of 6 to 12 times fuel by weight is atomized into thecombustion flame and vaporized in milliseconds. Salt or impuritiesentrained in the steam are separated from steam and then crystallized,precipitated and/or filtered leaving behind clean steam.

Salt or waste collection and removal mechanism 80 can be accomplished byany of a number of well-known means from combustion chamber 25, such asby a rotary longitudinal auger. This auger is sealed so as not to bypassmuch pressurized working gases as it rotates and removes theprecipitated salt. As mentioned above, an alternative is to spray themolten waste or salt through spray nozzles into a collecting tower orextrude the salt 81 into strands or rods which can then be cut todesired sizes. A still further alternative is to drain the molten saltdirectly into molds to form salt blocks 81 which are then easy totransport and use in chemical processing reprocessed for recovery orotherwise disposed of.

The resulting working fluid, which now includes clean water steam, maybe fed into one or more standard steam or gas turbines. Following workproduction by the expanding steam-gas mixture, a condenser 62 condensessteam 61 resulting in a source of usable potable water 65. Using thisopen cycle at pressure ratios of from 10:1 to 50:1 or higher electricpower may be generated at good efficiencies and specific fuelconsumption.

FIG. 6 shows a second embodiment of a unit using the VAST cycle. In thisembodiment, the efficiency of the system is further increased bycapturing additional waste heat from the combustion chamber 25. Thecombustion chamber 25 is enclosed in a double shell heat exchanger 90.In the version shown, the hot compressed air 11 exiting the compressor10 passes through the shell 92 immediately surrounding the combustionchamber 25 before it enters the combustor 25. The cold water 41 is fedto a second shell 94 which surrounds the first shell 92. In this mannerthe air 11 absorbs additional heat normally lost from the combustor 25and the incoming water 41 absorbs some of the heat from the compressedair 11. An additional benefit, since the air 11 is at an elevatedpressure, is that the pressure differential across the combustionchamber 25 wall (i.e. the difference between the combustor interior andambient conditions as in FIG. 5 or the difference between the combustorinterior and the compressed air 11 is significantly reduced, thusreducing the stress on the combustor wall from the combination of hightemperature and high pressure. The water 41, after passing through thecombustion chamber outer shell 94, then proceeds through the condenser62 and the heat exchanger 73 to acquire the desired injectiontemperature. Care is taken to maintain the water under pressure possiblyas high as 4000 psi so that, as the water is heated, it does not convertto steam before it is injected into the combustion chamber 25 which isat a higher temperature and, in most instances, a lower pressure thanthe superheated water 41.

Purification of contaminated waste products or treatment of solid,liquid and gaseous waste products from commercial processes resulting inuseable products with power production as a by-product are alsopotential applications of an engine employing the VAST cycle. Wastewater from dried solid waste products may be used in the presentinvention, resulting in filtered, useable water as one byproduct. Thecombustible materials are additional fuel for burning in the combustor25 and the inorganic dried waste products may then be used to createfertilizers. As is apparent, other chemicals can be extracted from solidand liquid products using the present invention. Sewage treatment isalso an application. Other applications include water softening, steamsource in conjunction with oil field drilling operations and wellproduction, recovery and recycling of irrigation water along withfertilizer and minerals leached from the soil, municipal solid waste,etc.

2. Aircraft Engines

The VAST cycle described about, particularly when operated with recycledwater, is particularly efficient and has a relatively low fuelconsumption when used in commercial aircraft which normally operates at30,000 to 40,000 feet. At such elevations ambient pressure is 0.1 to0.25 atmospheres or lower and ambient temperature is well below 0° F.Examples 5-7 open cycle data illustrate the benefit of lowering turbineexit pressure. To generate turbine exit pressures below atmosphere, suchas when operating the system at sea level, a vacuum pump on the turbineexit is necessary. This pump, which consumes energy generated by thesystem, reduces the usable energy and efficiency of the system.

Elimination of the turbine exit vacuum pump by operating in anenvironment with pressures less that atmosphere, such as at elevationsgreater than about 30,000 feet, increases the usable power output of thesystem, and therefore, reduces fuel consumption. Further, if the waterin the system is to be recycled, the ambient air temperature can be usedto condense and cool the exiting gas stream and separate the water forrecycling reducing the amount of energy used to recover the heat.

3. Steam Generation and Steam/Power Cogeneration

It is also contemplated that the combustor and its control system, alongwith a suitable compressor can be used without the power turbine solelyfor the generation of high temperature, high pressure steam, thegeneration of potable water, or the recovery of valuable inorganicmaterials dissolved in the water. Alternatively, one or more gas and/orsteam turbines sized to produce a desired amount of electrical energycan be coupled to the combustor to deliver electrical energy as well amix of high temperature, high temperature steam as a side streamdirectly from the combustor.

While various embodiments of the present invention have been shown forillustrative purposes, the scope of protection of the present inventionis limited only in accordance with the following claims and the spiritand scope of the appended claims should not be limited to thedescription of the preferred versions contained herein.

What is claimed is:
 1. A power generating system comprising: acompressor configured for compressing ambient air into compressed airhaving a pressure greater than at least about four atmospheres and anelevated temperature; a combustion chamber connected to the compressor,wherein the combustor is configured to receive flow of compressed airfrom the compressor; fuel injection means for injecting fuel into thecombustion chamber; liquid injection means for injecting a vaporizablenon-flammable liquid into the combustion chamber; a combustioncontroller for independently controlling the quantity, pressure andtemperature of the compressed air, the fuel delivered to the fuelinjection means, and the vaporizable liquid delivered to the liquidinjection means so the injected fuel and at (cast a portion of thecompressed air is combusted and the injected liquid is transformed intoa vapor in the combustor to create, in the combustion chamber, a workingfluid consisting of a mixture of unburned compressed air components,fuel combustion products and the vapor during combustion at apredetermined combustion temperature; and a work engine coupled to andsupplied with the working fluid formed in the combustion chamber.
 2. Thepower generating system according to claim 1 further including anignition sparker for igniting the injected fuel and compressed air. 3.The power generating system according to claim 1, wherein the powergenerating system further including: condenser means for condensing adesired portion of the vapor from the working fluid; and exhaust meansfor exhausting the remaining portion of the working fluid.
 4. The powergenerating system according to claim 1 further including: condensermeans for condensing the vapor from the working fluid exiting the workengine back to a vaporizable liquid, recycle means for delivering saidvaporizable liquid to the liquid injection means, and exhaust means forexhausting the remainder of the working fluid to the compressor forrecompression.
 5. The power generating system according to claim 1further including one or more additional combustion chambers receivingthe compressed air, fuel and vaporizable non-flammable liquid configuredsuch that working fluid from all combustion chambers is delivered to oneor more work engines.
 6. The power generating system according to claim1 wherein the work engine receiving the work working fluid is selectedfrom the group consisting of one or more of a steam turbine, gasturbine, reciprocating, Wankel, and cam engine engines, and shaft driveunits.
 7. The power generating system according of to claim 1, whereinthe compressor and work engines are turbine type devices, and whereinsaid devices are connected by at least one shaft.
 8. The powergenerating system according to claim 1, wherein the combustioncontroller controls the combustion temperature using informationtransmitted from temperature detectors located in the combustionchamber.
 9. The power generating system according to claim 1, whereinthe combustion control means controller controls the liquid injectionmeans and fuel injection means during combustion such that the weightmass flow of injected liquid is at least about two times the weight massflow of injected fuel so that the quantity of delivered vaporizableliquid is controlled to maintain the average temperature of the workingfluid delivered to a desired work engine to a desired operatingtemperature.
 10. The power generating system according to claim 9,wherein the combustion control means controller controls the air flowand fuel injection means such that the ratio of weight of injected fuelto weight of injected air is from about 0.03 to about 0.066 duringcombustion.
 11. The power generating system according to claim 10,wherein the combustion controller independently controls the averagecombustion temperature and the fuel to air ratio.
 12. The powergenerating system according to claim 9, wherein: the combustiontemperature is controlled by the combustion control means controller sothat the air to fuel ratio is selected to obtain stoichiometric burningand the temperature of the working fluid is adjusted by controlling thedelivery of the quantity of non-flammable vaporizable liquid, thetemperature adjustment being provided substantially only by the latentheat of vaporization of said liquid.
 13. The power generating systemaccording to claim 9, wherein at least about 95% of the oxygen in thecompressed air is combusted in the combustion chamber.
 14. The powergenerating system according to claim 9, wherein the pressure of thecompressed air is maintained at a pressure of 4 to 100 atmospheres,while entropy of the engine is held substantially constant.
 15. Thepower generating system according to claim 1, wherein the pressure ofthe compressed air is maintained constant while the temperature ofcombustion and the quantity of working fluid is varied, by thecombustion controller by adjustment of the quantity of non-flammablevaporizable liquid fed to one or more liquid injection means locatedthroughout the combustion chamber.
 16. The power generating systemaccording to claim 1 wherein all chemical energy in the injected fuel isconverted during combustion into thermal energy, the non-flammableliquid is water, and vaporization of the water into steam createscyclonic turbulence that assists molecular mixing of the fuel and airsuch that stoichiometric combustion is effectuated.
 17. The powergenerating system according to claim 1 wherein the liquid injectionmeans is a series of one or more nozzles located in the combustionchamber fed by a pressurized liquid supply.
 18. The power generatingsystem according to claim 1 wherein the liquid injected into thecombustion chamber is water which is transformed into steam and whichcools the combustion products are cooled substantially, solely by thelatent heat of vaporization of water.
 19. The power generating systemaccording to claim 18 wherein the injected water absorbs heat energy sothat the temperature of the working fluid is reduced to that of amaximum operating temperature of the work engine.
 20. The powergenerating system according to claim 18 wherein the injected water istransformed by way of a flash process into steam at the pressure of thecombustion chamber without additional work for compression and withoutadditional entropy.
 21. The power generating system according to claim18, wherein the engine is a power turbine powered by the working fluidconsisting essentially of steam, unoxidized nitrogen, inert gases in thecompressed air, carbon dioxide and non-flammable components of the fuelcomprising steam, nitrogen, inert gases, carbon dioxide, excess oxygen,un-burned components of the fuel, and pollutants.
 22. The powergenerating system according to claim 18, wherein the water injected isused to control the combustion temperature and the maximum operatingtemperature of the work engine and to prevent the formations of gasesand compounds that cause or contribute to the formation of atmosphericsmog.
 23. The power generating system according to claim 1 wherein thefuel injection means comprises at least one nozzle located in to deliverfuel into the combustion chamber, said nozzle being fed by a pressurizedfuel supply.
 24. The power generating system according to claim 21wherein the fuel supply is selected from the group consisting of dieselfuel, well-head oil, propane, natural gas, methane, gasoline, alcoholand mixtures thereof.
 25. The power generating system according to claim1 wherein the injected liquid is non-potable water, and further includesmeans in the combustor to remove inorganic materials from the waterafter vaporization and collect such inorganic materials from thecombustor.
 26. The power generating system according to claim 24 25further including a condenser for collecting potable water after thenon-potable water has been vaporized in the combustion chamber.
 27. Thepower generating system according to claim 1 wherein during theoperation of the engine in excess of a predetermined rpm, waterinjection and the portion of compressed air combusted is constant withrespect to fuel as engine rpm increases, and during the operation of theengine between the first and a second predetermined rpm the water/fuelratio and the air/fuel ratio increases, and below the secondpredetermined rpm, water/fuel ratio and air/fuel ratio are heldconstant.
 28. The power generating system according to claim 27 1,wherein the ratio of water weight to fuel weight injected ranges fromabout 8 to 1 to about 1:1 as the rpm of the engine is increased.
 29. Amethod of operating a power generating system comprising the steps of:compressing ambient air into compressed air having a pressure of atleast about four atmospheres, and having an elevated temperature;delivering the compressed air into a combustion chamber; injectingcontrolled amounts of fuel into the combustion chamber; injectingcontrolled amounts of a non-flammable liquid into the combustionchamber; independently controlling the amount of compressed air, theamount of fuel injected, and the amount of liquid injected so as tocombust the injected fuel at least a portion of the compressed air andto transform the injected liquid into a vapor; wherein a working fluidconsisting of a mixture of a non-flammable components of the compressedair, fuel combustion products and vapor is generated in the combustionchamber during combustion at a predetermined combustion temperature. 30.The method of claim 29 further including the step of igniting the fuelusing an ignition sparker igniter.
 31. The method of claim 29, whereinthe power generating system further includes including the steps of:condensing a desired portion of the vapor from the working fluid; andexhausting the remaining portion of the working fluid.
 32. The method ofclaim 29, wherein the power generating system further includes the stepsof: condensing the vapor from the working fluid, delivering at least aportion of the condensed vapor back into the combustor, and deliveringat least a portion of the remainder of the working fluid to the adownstream compressor for recompression.
 33. The method of claim 29further including the step of delivering the working fluid to at leastone work engine.
 34. The method of claim 29, wherein the compressed airis further heated by contact within outer surfaces of the combustionchamber prior to being delivered into the combustion chamber.
 35. Themethod of claim 29, wherein the amount of liquid and fuel injected iscontrolled during combustion such that the ratio of weight of injectedliquid to weight of injected fuel is at least about two to one so as tocontrol the average temperature in the combustion chamber to a deliverdesired work engine operating temperature.
 36. The method of claim 35,wherein the air flow and fuel injection is controlled such that theratio of weight of injected fuel to weight of injected air isapproximately 0.03 to 0.066 during combustion.
 37. The method of claim36, wherein the average temperature in the combustion chamber and thefuel to air ratio are independently controlled.
 38. The method of claim37, wherein the combustion temperature is controlled to obtain completecombustion of the fuel with the conversion of all carbonaceous materialfed to the combustion chamber to CO₂.
 39. The method of claim 35,wherein at least 95% of the oxygen in the compressed air is combusted inthe combustion chamber.
 40. The method of claim 35, wherein the pressureof the compressed air is maintained at a pressure of 4 to 100atmospheres, while entropy of the engine is held approximately constant.41. The method of claim 29, wherein the pressure of the compressed airis maintained constant while the temperature and quantity of workingfluid is are varied.
 42. The method of claim 29 wherein all chemicalenergy in the injected fuel is converted during combustion into thermalenergy and the vaporization of liquid creates turbulence in thecombustion chamber to cause intimate mixing of the fuel and air suchthat complete combustion is effectuated.
 43. The method of claim 29wherein: the liquid injected into the combustion chamber is water whichis transformed into steam following injection into the combustionchamber; and the temperature in the combustion chamber is controlledsubstantially totally by way of the latent heat of vaporization of suchwater.
 44. The method of claim 43 wherein the quantity of injected wateris chosen so as to absorb the heat energy caused by combustionsufficient to reduce the temperature of the working fluid to a desiredwork engine operating temperature.
 45. The method of claim 43 whereinthe injected water is transformed by way of a flash process into steamat a pressure of the combustion chamber without additional work forcompression and without additional entropy or enthalpy.
 46. The methodof claim 43, wherein the working fluid is comprised substantially onlyof steam, unoxidized nitrogen, non-flammable unburned components of thecompressed air and fuel, and carbon dioxide.
 47. The method of claim 43,wherein the water injection is used to control the combustiontemperature and to prevent the formations of gases and compounds thatcause or contribute to the formation of atmospheric smog.
 48. The methodof claim 29 wherein the injected fluid is non-potable water, and furtherincluding the steps of vaporizing the non-potable water in thecombustion chamber and removing any contaminating materials dissolved inthe non-potable water from the combustion chamber separately from theworking fluid.
 49. The method of claim 48 further including the step ofcondensing potable water from the working fluid after the non-potablewater has been vaporized in the combustion chamber.
 50. The methodaccording to claim 29 wherein during the operation of the powergenerating system at greater than a predetermined rpm, liquid injectionand the portion of compressed air combusted is held constant withrespect to fuel as engine rpm increases, during the operation of theengine between the first and a second predetermined rpm, the liquid/fuelratio and air/fuel ratio is increased, and below the secondpredetermined rpm, the liquid/fuel ratio and air/fuel ratio are heldconstant.
 51. The method of claim 43 wherein cooling of the engine iseffectuated with water and without dilution air.
 52. A process ofcontinuously delivering a working fluid to the exit of an enginecombustion chamber, the working fluid having enhanced power generatingcapacity when compared with the working fluid produced by an engineoperating only with a fuel and air feed, comprising: a) creating acombustible mixture by continuously combining fuel under pressure andcompressed air in the combustion chamber, the air being fed in a fixedratio to the fuel, the fixed ratio providing air in at least astoichiometric quantity, b) igniting the combustible mixture to create acontinuously burning flame which produces a hot gas stream of combustionproducts having a pressure at least as great as the pressure of thecompressed air, and c) injecting a vaporizable, non-flammable liquidinto the hot gas stream to reduce the temperature of the hot gas stream,the liquid prior to being injected being maintained at a pressure inexcess of the pressure in the combustion chamber to maintain thenon-flammable liquid in a liquid state prior to injection into thecombustion temperature, the injected inert liquid flashing to vaporimmediately upon entering the combustion chamber, the combination of thehot gas stream and vapor constituting the working fluid, the quantity ofinert liquid and the temperature of the inert liquid being selected toproduce a preset temperature in the working fluid at the exit of thecombustion chamber, the temperature and dwell time of the hot gas streamof combustion products being controlled to cause substantially fullcombustion of the fuel while the temperature of the working fluid iscontrolled to minimize formation of nitrogen oxides and maximizeformation of carbon dioxide, the process continuing until the need fordelivery of the working fluid ceases to exist.
 53. The process of claim52 wherein the quantity of compressed air entering the combustionchamber is slightly in excess of the stoichiometric amounts so that atleast about 95% of the oxygen in the air is consumed in the burning ofthe combustible mixture.
 54. The process of claim 52 wherein the liquidis water and the temperature of the working fluid exiting the combustionchamber is controlled to a selected temperature between about 750° F.and about 2500° F. by the injection of the water.
 55. The process ofclaim 54 wherein the temperature of the working fluid exiting thecombustion chamber is controlled to a selected temperature between about1800° F. and about 2200° F. by the injection of the water.
 56. Theprocess of claim 54 A process of continuously delivering a working fluidto the exit of a combustion chamber, the working fluid having enhancedpower generating capacity when compared with working fluid produced in acombustion chamber operating only with a fuel and air feed, comprising:a) creating a combustible mixture by continuously combining fuel underpressure and compressed air in the combustion chamber, the air beingprovided in at least a stoichiometric quantity, b) igniting thecombustible mixture to create a continuously burning flame whichproduces a hot gas stream including combustion products, and c)injecting a vaporizable, liquid thermal diluent into the hot gas streamto reduce the temperature of the hot gas stream, the injected liquidthermal diluent rapidly becoming a vapor upon entering the combustionchamber, the combination of the hot gas stream and vapor constitutingthe working fluid, the quantity and the temperature of the thermaldiluent being selected to produce a desired temperature in the workingfluid at the exit of the combustion chamber, the temperature and dwelltime of the hot gas stream being controlled to cause substantially fullcombustion of the fuel while the temperature of the working fluid iscontrolled to minimize formation of nitrogen oxides and maximizeformation of carbon dioxide, wherein the thermal diluent is water andthe temperature of the working fluid exiting the combustion chamber iscontrolled to a selected temperature between about 750° F. and about2500° F. by the injection of the water, the temperature of the waterjust prior to injection is at a temperature not more than about 50° F.below that of the working fluid exiting the combustion chambercontrolled between about 595° F. and about 700° F.
 57. The process ofclaim 52 further including, after step c), directing the working fluidinto a turbine power generator, at least a part of the working fluidexiting the turbine being used to heat the non-flammable liquid prior toinjection into the working fluid.
 58. The process of claim 57 whereinthe fuel is diesel oil number 2, the f/a is 0.066, and for every 1 poundper second of air feed the turbine power generator produces in excess of650 horsepower at a fuel efficiency in excess of about 36 percent and ansfc of less than about 0.36.
 59. The process of claim 52 wherein thefuel is selected from the group consisting of diesel fuel number 2,ethanol, sulphur free heating oil, well-head oil, propane, methane,natural gas, gasoline and mixtures thereof.
 60. The process of claim 57wherein for every 1 pound per second of air feed the turbine powergenerator produces in excess of 750 horsepower at a fuel efficiency inexcess of about 42 percent and an sfc of less than about 0.32.
 61. Theprocess of claim 52 A process of continuously delivering a working fluidto the exit of a combustion chamber, the working fluid having enhancedpower generating capacity when compared with working fluid produced in acombustion chamber operating only with a fuel and air feed, comprising:a) creating a combustible mixture by continuously combining fuel underpressure and compressed air in the combustion chamber, the air beingprovided in at least a stoichiometric quantity, b) igniting thecombustible mixture to create a continuously burning flame whichproduces a hot gas stream including combustion products, and c)injecting a vaporizable, liquid thermal diluent into the hot gas streamto reduce the temperature of the hot gas stream, the injected liquidthermal diluent rapidly becoming a vapor upon entering the combustionchamber, the combination of the hot gas stream and vapor constitutingthe working fluid, the quantity and the temperature of the thermaldiluent being selected to produce a desired temperature in the workingfluid at the exit of the combustion chamber, the temperature and dwelltime of the hot gas stream being controlled to cause substantially fullcombustion of the fuel while the temperature of the working fluid iscontrolled to minimize formation of nitrogen oxides and maximizeformation of carbon dioxide, wherein the inert liquid thermal diluent isnon-potable water and the process further includes the steps of:collection ofcollecting inorganic materials dissolved in the non-potablewater in the combustion chamber, and the conversion ofconverting theinorganic materials to a solid form.
 62. The power generating system ofclaim 1 further including at least one heat transfer means positionedexternal and circumferential to the combustion chamber and extendingalong a substantial portion of the length of the combustion chamber suchthat the compressed air flows over external surfaces of the combustionchamber prior to entering the combustion chamber, the temperature of thecompressed air being elevated by heat radiated from said externalsurfaces.
 63. The power generating system of claim 62 wherein the heattransfer means comprises at least two contiguous circumferentalcircumferential chambers.
 64. A power generating system comprising a) acombustion chamber, b) a work engine coupled to the combustion chamber,c) fuel supply means for delivering fuel to the combustion chamber, d)air supply means for delivering compressed air at an elevatedtemperature and at a constant pressure to the combustion chamber theamount of air being chosen so that at least about 90% of the oxygen inthe air is consumed when burned with the fuel, the fuel and air beingmixed in the combustion chamber, e) control means to vary the quantityfor controlling the delivery of air supplied to the combustion chamberand to adjust the amount of fuel supplied fuel to the combustion chamberso that the fuel to air ratio remains about constant, f) a fuel igniterfor igniting the mixture of fuel and air to produce a combustion vaporstream, g) liquid supply means for delivering superheated water underpressure to the combustion chamber, the water being convertedsubstantially instantaneously upon entering the combustion chamber tosteam, the delivery and formation of steam creating turbulence andmixing in the combustion chamber resulting in a working fluid composedof steam, combustion products and non-flammable materials in the air andfuel, said working fluid being delivered to the work engine, h) acombustion chamber temperature controller, said controller deliveringthe superheated water to the combustion chamber in quantities sufficientto maintain the temperature of the working fluid at a desired level,substantially all of the control of the temperature in the combustionchamber being derived from the latent heat of vaporization of the waterintroduced into the combustion chamber, and i) heat exchanging means fortransferring heat from the working fluid exiting the work engine to thewater, said heat elevating the temperature of the water from a feedtemperature to the desired temperature for delivery to the combustionchamber.
 65. The process system of claim 64 also, further including thestep a means of delivering additional non-flammable liquid water to thecompressed air prior to introduction of the compressed air into thecombustion chamber.
 66. The process system of claim 64 wherein thecompressed air is mixed with the fuel in at least two stages such that aportion of the air is mixed with the fuel, the fuel is ignited and thenthe remainder of the air is added to the fuel at a point downstream ofthe fuel igniter.
 67. The process of claim 66 wherein about 50% of thecompressed air is mixed with the fuel in a first zone of a burner at oneend of the combustion chamber, said mixture of air and fuel is ignitedto produce a fuel rich flame, about 25% of the air is added to fuel richflame in a second zone of the burner located down stream from the firstzone, about 1.2.5% of the air is added to the flame in a third zone ofthe burner located down stream from the second zone, and the remainderof the air is added to the flame in a fourth zone of the burner locateddown stream from the third zone.
 68. The process of claim 67 whereincontrolled amounts of the water are injected into the combustion chamberat multiple locations in the combustion chamber downstream from thefourth zone of the burner.
 69. The process of claim 66 whereincontrolled amounts of the water are also injected into the compressedair prior to mixing of the air with the fuel.
 70. The process of claim66 wherein, prior to mixing the air with the fuel, the compressed air isheated by heat radiating from the combustion chamber by passing saidcompressed air through a channel external to the combustion channel, atleast one wall of the chamber being an outer wall of the combustionchamber.
 71. The process of claim 67 wherein, prior to mixing the airwith the fuel, the compressed air is heated by heat radiating from thecombustion chamber by passing said compressed air through a channelexternal to the combustion channel, at least one wall of the chamberbeing an outer wall of the combustion chamber.
 72. The process of claim71 wherein the working fluid exiting the work engine contains less than3 ppm NO_(x).
 73. The process of claim 71 wherein the working fluidexiting the work engine contains less than 3 ppm CO.
 74. The process ofclaim 71 wherein the working fluid exiting the work engine contains lessthan 3 ppm CO and less than 3 ppm NO_(x).
 75. A generating systemcomprising a) a combustion chamber, b) fuel supply means for deliveringfuel to the combustion chamber, c) air supply means for deliveringcompressed air at an elevated temperature and at a constant pressure tothe combustion chamber the amount of air being chosen so that at leastabout 90% of the oxygen in the air is consumed when burned with thefuel, the fuel and air being mixed in the combustion chamber, d) controlmeans to vary the quantity of air supplied to the combustion chamber andto adjust the amount of fuel supplied to the combustion chamber so thatthe fuel to air ratio remains constant within a desired range, e) a fueligniter for igniting the mixture of fuel and air to produce a combustionvapor stream, f) liquid supply means for delivering superheated waterunder pressure to the combustion chamber, at least part of the waterbeing rapidly converted substantially instantaneouslyto steam uponentering the combustion chamber to steam, the delivery and formation ofsteam creating turbulence and mixing in the combustion chamber resultingin a working fluid composed of steam, combustion products unreactedcomponents of the air and non-flammable materials in the air andunburnedfuel, said working fluid being a high temperature steam streamdeliverable to an external piece of equipment at a controlled pressurerequired by that external piece of equipment, g) a combustion chambertemperature controller, said controller delivering the superheated waterto the combustion chamber in quantities sufficient to maintain thetemperature of the working fluid at a desired level, substantiallyallmost of the control of the temperature in the combustion chamberbeing derived from the latent heat of vaporizationa change in enthalpyof the water introduced into the combustion chamber, and h) heatexchanging means for transferring heat from the working fluid exitingthe work engine external piece of equipment to the water, said heatelevating the temperature of the water from a feed temperature to the adesired temperature for delivery to the combustion chamber.
 76. A methodof operating a power generating system comprising the steps of:compressing ambient air into compressed air having a pressure of atleast about four atmospheres, and having an elevated temperature;delivering the compressed air into a combustion chamber; injectingcontrolled amounts of fuel into the combustion chamber; injectingcontrolled amounts of a non-flammable liquid into the combustionchamber; independently delivering additional non-flammable liquid to thecompressed air prior to introduction of the compressed air into thecombustion chamber; independently controlling the amount of compressedair, the amount of fuel injected, and the amount of liquid injected soas to combust the injected fuel and at least a portion of the compressedair and to transform the injected liquid into a vapor; wherein a workingfluid consisting of a mixture of a non-flammable components of thecompressed air, fuel combustion products and vapor is generated in thecombustion chamber during combustion at a predetermined combustiontemperature.
 77. The power generating system according to claim 1,wherein the amount of water injection and the amount of compressed aircombusted are kept constant.
 78. The power generating system accordingto claim 1, wherein the water to fuel ratio is increased as the amountof excess air is decreased.
 79. The power generating system according toclaim 1, wherein the ratio of injected water to fuel is held constantand the amount of compressed air combusted is held constant.
 80. Thepower generating system according to claim 4, further including acompressor to recompress and exhaust the remainder of the working fluidto at least ambient pressure.
 81. The method of claim 29, wherein atleast 81% of the oxygen in the compressed air is combusted in thecombustion chamber.
 82. The power generating system according to claim 1further including at least a second work engine coupled to receiveworking fluid from the combustor.
 83. The power generating systemaccording to claim 1, further including at least one temperaturedetector operative to determine temperature in the combustion chamber.84. The power generating system according to claim 1, wherein: thecombustion controller is operative to select the air to fuel ratio toobtain stoichiometric burning and the temperature of the working fluidis adjusted by controlling the delivery of the quantity of non-flammablevaporizable liquid, the temperature adjustment being providedsubstantially by the vaporization of said liquid.
 85. The powergenerating system of claim 1, further including at least one heattransfer device positioned circumferentially around to the combustionchamber and extending along a substantial portion of the length thereof,the heat exchange device being constructed and configured such that thecompressed air flows therethrough over external surfaces of thecombustion chamber prior to entering the combustion chamber, thetemperature of the compressed air being elevated by heat from theexternal surfaces.